Generation of an ultrasonic beam using embedded fibre optic delivery and low power laser sources.

摘要

A linear array of embedded optical fibres was utilised to produce an ultrasonic beam in carbon composite plates as a potential tool for structural assessment. The embedded fibres were used to deliver laser pulses from low power (1.5W) modulated laser diode sources for the generation of the ultrasound. These were modulated with a pseudorandom binary sequency, which was used in conjunction with a correlation based detection technique using interferometric fibre optic sensors. Furthermore time delays could be used to adjust the excitation of the elements in the array, thus enabling the direction of the generated ultrasonic beam to be controlled.